The purpose of this intervention was to conduct a Licence Condition (LC) compliance inspection at EDF Energy Nuclear Generation Limited's (NGL's) Torness Power Station in line with the planned inspection programme contained in the Torness Integrated Intervention Strategy (IIS) for 2016/17.
As part of this intervention, two ONR structural integrity specialist inspectors and the nominated site inspector performed a compliance inspection against the following Licence Condition (LC):
The inspection was conducted to support an overall ONR intervention on assessing the licensee's arrangements for the fleetwide management of corrosion. To align with ONR's strategy for this intervention, each of the licensee's nuclear licensed sites has been targeted to sample local site arrangements for managing corrosion of pipework on systems which may affect safety, with an emphasis on the management of Corrosion Under Insulation (CUI).
No safety system inspection was undertaken, hence this is not applicable.
In our opinion and from the information sampled, Torness demonstrated that adequate arrangements are in place for the regular and systematic examination, inspection maintenance and testing of the Secondary Shutdown and Emergency Generation pipework that may affect safety. We are satisfied that the level of inspection, combined with corrosion training, plant walk downs and Corrosion Co-ordinator involvement, is likely to have identified areas susceptible to CUI.
In relation to the CO2 pipework, Torness were not currently able to fully demonstrate that all areas of the system susceptible to CUI have been inspected fully, although we accept that activity is underway to address this issue. We consider that it would be beneficial for Torness to conduct and document a methodical review of the CO2 plant to identify which areas have been inspected and to document that the remaining pipework is safe to operate.
Although areas for improvement have been identified, it is acknowledged that NGL are introducing measures to address them. We judged that the LC28 arrangements and their implementation, associated with concealed pipework and corrosion under insulation currently conform to a green rating (no formal action), but recommend further monitoring once the revised processes have been adopted by Torness. One category 4 ONR issue (number 4713) has been raised to track the progression of the actions raised during the visit. In addition, a level 3 ONR issue (number 4473) has been raised to monitor the fleet-wide response to the management of corrosion under insulation.
There were no findings from this inspection that could significantly undermine nuclear safety or which would result in changes to the planned interventions and inspections of Torness Power Station.